The present invention relates to roller bearing structures and means for supporting and spacing the roller bearings with respect to each other. More specifically, the present invention relates to a metal window cage for shoulderless self-aligning roller bearings which are capable of carrying high loads and in which the inner end surfaces of the rollers are almost in engagement with each other.
Cages for self-aligning bearings are known which have an H-shaped cross-section, as seen in German Utility Model Gm 17 90 657. Such a cage supports two annular rows of bearing rollers. The two halves of the cage in such a bearing rest against each other with clearance at their rear or inner, i.e. their adjacent, surfaces. The cages are also provided witih circumferential radially outer surfaces, which are shaped to correspond to the raceway of the outer bearing ring and have clearance from the outer ring.
Such cages, however, cannot advantageously be used in connection with self-aligning roller bearings which are to carry high loads and in which the inner end surfaces of the rollers in the two rows are, for all practical purposes, virtually in engagement with each other. This is so because the adjacent rear surfaces of the cage halves require too much space axially and this space is not present in bearings of the aforementioned type of the invention.
In the prior art, an additional disadvantage arises in that the rear surfaces of the cage do not permit elastic radial deformation of the cage which is required in order to insert the cage into the bearing. The radially extending rear surfaces tend to stiffen the cage and permit only a slight variation from the true round condition to a slightly oval condition. This slight variation is, however, not sufficient for introducing the cage by slight elastic deformation through the smallest outer ring diameter.
The cage deformation method of mounting is possible with a cage made in accordance with British Pat. No. 483,625. But, with a collar-like cage of that type, because the cage webs, which engage the sides of the rollers, lie far outside the pitch circle, there is the danger that the rollers are not sufficiently restrained axially and radially and may run onto the cage webs. In addition, the bearing shown in British Pat. No. 483,625 is not the type of bearing to which the present invention is directed.
In U.S. Pat. No. 1,144,451, after insertion of the rollers, one side of the cage edge of the tapered roller bearing cage is provided with indentations which hold the cage in the bearing and form a single structural unit. The indentation of the side edge of the cage is not only expensive in assembly, but it also is not possible to make such indentation when the cage is made of hardened material or cannot be indented with sufficient precision. In addition, the bearing of U.S. Pat. No. 1,144,451 is not of the same type as the bearing to which the present invention is directed.